Patent GB-194427-A (GB)
Abstract: 194,427. Automatic Telephone Manufacturing Co., Ltd., and Gillings, C. Dec. 17, 1921. Automatic exchange systems; metering systews.-In a system comprising a network of exchanges, a call is made by dialling the first three letters of the name of the wanted exchange followed by the four-digit number of the wanted subscriber, the whole seven-digit designation being recorded on a register-controller which translates the three exchange digits into a series of digits representing the position of the wanted exchange relatively to the calling exchange in the general trunking scheme. The four final digits are retransmitted by the register-controller without modification. The claims relate (1) to various forms of register-controller, which in all cases are of the type in which impulses are positively generated to operate the selectors, and (2) to arrangements by which the register-controllers affect a variable metering of a call in accordance with the exchange to which the call is extended. Figs. 1, 4 and 5 show one form of system, while Fig. 6 shows a modification of the registering part of the register-controller, and Figs. 8 and 9 show modifications of the sending part. Registration of the wanted exchange and number. The line relay 16, Fig. 1, energized as soon as an idle trunk is found by the line switch C, energizes relay 21, which starts the switch F to find an idle register - controller, whereupon the switching relay 23 becomes energized and energizes relay 37. Dialling tone is sent to the calling line over a circuit 46, 43, 42, 47. The first digit is repeated by relay 16 over circuit 40, 41, 42, 43 to magnet 45, which steps the switch MS to select one out of nine two-co-ordinate registers SS. At the termination of the digit, the sluggish series relay 42 relapses, followed by the relay 52 which it controls, and in the interval an impulse is sent over contacts 55, 53 to magnet 54, which steps the switch MDS to its second position. The second and third digits are repeated to the vertical and rotary magnets 57, 59 of the selected register SS and subsequent digits to the magnets 69, 75, &c. of the thousands, hundreds, &c. registers NS<I> - - NS<IV>, Fig. 4, the switch MDS moving to its next position after each digit and arriving finally at its eighth position. Impulse sending operations of the register-controller. The selection and setting of the switch SS by the three exchange digits energizes a code relay CR, Fig. 4, individual to the wanted exchange. The relay CR prepares a circuit 83, 85, 86, 87, 88, 89, 90, 91, 92, so that at the next closure of contact 92 by cam 94, relay 87, Fig. 5, becomes energized and locks itself, and at each subsequent closure of contact 98 by cam 93, relay 97 is .energized and transmits an impulse, by opening the bridge 100, 101 across the selector E<1>, at the same time sending an impulse over circuit 107 to the stepping magnet 114 of the sending-switch SS<I>. When the wiper 115 of this switch reaches the contact grounded by the exchange code relay CR, relay 118 is energized and locks itself up and unlocks the circuit 85 of the relay 87, so as to stop the transmission of further impulses. As soon as the selector E<1> has found an idle second selector in the selected level, the line and release relays 138, 127 successively relapse and a booster circuit B<2>, 101 is momentarily closed to energize a marginal relay 135, Fig. 5, which locks itself, and if, or as soon as, the register NS<I> has left its normal position, relay 121 is energized in a circuit 70, 120, 122 and establishes a fresh circuit 38, 140, 141, 85, 86, 87, 88, 90, 91, 92 for relay 87, so that a second series of impulses is initiated. The circuit 107 is now connected over contact 143 to the magnet 142 of the sending switch SS<II>, so that this series of impulses is terminated when the wiper 144 reaches the contact grounded by the code relay CR. Subsequent digits are similarly transmitted under control of the sending switches SS<III>, SS<IV>, &c. and registers NS<I>, NS<II>, &c., the transmission of each digit being delayed until the next register has left its normal position and until a booster impulses has been sent back by the last-operated selector to energize relay 135. Release of the register-controller; metering. The relay 149, energized after the sending of the final digit, grounds the circuit 151 to restore the various registers and sending switches, and prepares a circuit 155, 153, 152, 154, 43, 42, 157, 158 to energize relay 159, Fig. 1, at the next closure of contact 155 by cam 156. Relay 159 locks itself, switches the connection through, and prepares a circuit 163, 162, 48, 165, 167, 168 which is closed by a cam 169 a number of times corresponding to the charge for the exchange to which the called subscriber belongs, and the magnet 163 advances a switch MR a corresponding number of steps. Contact 175 is then closed by cam 170 to energize relay 178, which locks itself, opens the circuit of magnet 163, and unlocks relay 21, which releases relay 23 to open the circuits leading to the register-controller. Relay 37 relapses and energizes the release magnets of the switches MDS, MS, SS. On the reply of the called subscriber the current in the calling line is reversed, so that at the next closure of contact 197 by cam 196 a polarized relay 18 is energized and prepares a circuit 198, 174, 199 over which the, meter M receives a number of impulses corresponding to the setting of the switch MR. Contact 203 is then closed by cam 204 to energize magnet 206 which releases the switch MR. Release of the register-controller if an undue interval occurs between the dialling of two digits. In this case a relay TA, Fig. 1, which is slow to energize but quick to release, closes a circuit 209, 42, 157, 158 to energize relay 159, which results in the release of the register-controller as already described. Modified exchange-register, Fig. 6. If comparatively few exchanges have to be provided for, say 25, the switch MS, Fig. 1, and its nine associated Strowger registers SS may be replaced by three simple switches OC', OC<2>, OC<3> and a hunting switch HS having 25 positions. After the setting of the switches OC<1>, OC<2>, OC<3> by the three exchange digits, a contact 70 is closed in the circuit of the stepping magnet 206 of the switch HS. When this switch arrives at a position corresponding to the code relay CR of the wanted exchange, wiper 201 engages a terminal to which battery has been connected by switch OC<2>, and at the same time wipers 200, 202 engage terminals to which ground has been connected by switches OC', OC<3>, and a consequent-pole relay SF is thus energized to disconnect magnet 20& and to energize the relay CR. A larger number of exchanges can be provided for by employing several switches HS which all hunt at the same time. Modified arrangement of sending-switches, Fig. 8. In this modification, the sending- switches IS' - - IS<6> are of the ordinary dial type, transmitting their impulses at contacts 313, 315 &c. during their return movements. The exchange senders IS<1>, IS<2> hunt to positions marked by the code relay CR. The thousands, hundreds, &c. senders IS<3>, IS', &c. are set by stepping magnets 300, 301, &c. which respond to the dialled digits. When the sender IS<1> reaches the marked position it is released by magnet 311 and transmits a corresponding number of impulses as it returns to normal. A relay 312, energized at the same time as magnet 311, locks itself, open-circuits the stepping-magnet 309, and keeps the magnet 311 energized during return. As soon as the sender IS' has moved off normal and relay 327 been energized by a booster impulse over circuit 101, relay 331 becomes energized and starts the sender IS<2>. Relay 338, energized together with the release magnet 321 when the sender IS<2> reaches the marked position, unlocks relay 331, transfers the circuit of relay 331 to the off-normal contact 340 of the sender IS<4>, and prepares a circuit for relay 341. This relay responds at the next energization of relays 327, 331, energizes the release magnet 322 of sender IS<3>, and prepares corresponding circuits for the next sender, and so on. Second modified arrangement of sending- switches, Fig. 9. In this modification, a multidigit sending-switch IS is employed of the kind described in Specification 5249/13. When the switch OS<1> reaches the position marked by the code relay CR, a relay 404 open-circuits the stepping-magnet 400 and energizes relay 410, which closes a circuit 413, 414, 409 to one of the ten marking wires TL to record the first digit on the sender IS. A moment later a sluggish relay 416 becomes energized and locks itself up, open-circuiting relay 410 and preparing a circuit by which relav 410 again becomes energized by relay 420 when the switch OS<2> reaches its marked position. The second energization of relay 410 closes a circuit 413, 423, 432, 433 to another marking- wire TL to record the second digit on the sender IS, and a moment later relay 431 becomes energized to transfer the circuits to the thousands switch NS', and so on. After the units switch NS<4> has recorded its digit on the sender IS, relay 437 closes a circuit SL to start the sender IS,. and after the sender has completed its operation it closes a circuit FL, 154 to energize the switch-. ing relay 159, Fig. 1.